Nitai guna-mani amar nitai guna-mani — this is a song sung by Locana Dasa Thakura, almost a contemporary of Lord Caitanya Mahaprabhu. He has got many books on the life and precepts of Lord Caitanya Mahaprabhu. So he is saying that Lord Nityananda is full of good qualities, guna-mani.
Guna-mani means the jewel of all qualities. So nitai guna-mani amar nitai guna-mani. He is repeatedly uttering that Lord Nityananda is the reservoir of all good qualities. Aniya premera vanya bhasailo avani. And on account of His spiritual qualities, he inundated the whole world by the flood of love of God. It is by His kindness people can feel what is love of God. Premer vanya loiya nitai aila gauda-dese. When Caitanya Mahaprabhu left home and took sannyas, He made His headquarter at Jagannatha Puri. So after His accepting the sannyas order, when He left His home and country Lord Nityananda Prabhu also accompanied Him up to Jagannatha Puri.
So after a few days, Lord Caitanya requested Him that "If both of us remain here, then who will preach in Bengal?" Bengal is known as gauda-dese. So under the order of Lord Caitanya Mahaprabhu, He brought from Him the flood of love of Godhead and He distributed in the whole of Bengal, gauda-dese. And in that flood of love of God, all devotees became drowned. Only those who were not devotees, they could not drown but they were floating, dina hina bache. But so far Nityananda Prabhu is concerned, He does not make any discrimination between devotees and nondevotees. Dina hina patita pamara nahi bache.
Poor or rich or enlightened or foolish, everyone could take the instruction of Lord Caitanya Mahaprabhu and become drowned in the ocean of love of Godhead. Such love of Godhead is brahmar durlabha. Even Lord Brahma, who is the supreme teacher within this universe, he also cannot relish. But by the grace of Lord Caitanya Mahaprabhu and Nityananda Mahaprabhu, this love of Godhead was distributed to everyone without any discrimination.
So abaddha karuna-sindhu, it was just like a big ocean blocked all sides. Ocean of love of Godhead is a big ocean, but it was not inundated. So Nityananda Prabhu cut a canal from the ocean, and He brought the canal in every door. Ghare ghare bule prema-amiyara ban. The flood of the nectar of love of Godhead was thus distributed in each and every home in Bengal. Actually still Bengal is overwhelmed when there is talk of Lord Caitanya Mahaprabhu and Nityananda Prabhu.
Locan bole, now the author is speaking on his behalf that anyone who does not take the advantage given by Lord Nityananda Prabhu, so in his opinion he thinks that such a person knowingly is committing suicide.
(Srila Prabhupada, speaking on September 24, 1972, in Los Angeles)